Sheep Creek

Prospect, Active

Alternative names

Gossan Peak

Commodities and mineralogy

Main commodities Pb; Zn
Other commodities Ag; Sn
Ore minerals cassiterite; galena; pyrite; sphalerite; stannite
Gangue minerals quartz; sericite

Geographic location

Quadrangle map, 1:250,000-scale HE
Quadrangle map, 1:63,360-scale D-3
Latitude 63.92
Longitude -148.28
Nearby scientific data Find additional scientific data near this location
Location and accuracy This prospect is at an elevation of about 700 feet near the head of Sheep Creek. It is in the NW1/4 of sec. 35, T. 11 S., R. 4 W., of the Fairbanks Meridian. The location is accurate to within 1 mile. This is locality 4 of Cox and others (1989).

Geologic setting

Geologic description

The Sheep Creek deposit is in the Totatlanika Schist near its contact with the Keevy Peak Formation (Nokleberg and others, 1994). The Totatlanika Schist ranges in age from Early Mississippian to Middle Devonian and consists mostly of felsic and mafic metavolcanic and metavolcaniclastic rocks (Wilson and others, 1998). The deposit is 200 feet thick and 2,000 feet long, and consists of isoclinally folded, stratabound lenses of massive sulfides in tuffaceous chlorite schist and chert (O'Connor and others, 1989). The sulfides are fine-grained sphalerite, galena, and pyrite. This deposit has high values of Sn, reported as either cassiterite or stannite. Channel sampling and grab samples contain up to 11% combined lead and zinc, and 10 grams of silver per ton. Zones up to 1 meter wide contain 1% tin (Nokleberg and others, 1994).
Geologic map unit (-148.28232566734, 63.9195539302683)
Mineral deposit model Kuroko massive sulfide (Cox and Singer, 1986; model 28a)
Mineral deposit model number 28a
Age of mineralization Mineralization is syngenetic with the Paleozoic host rocks.
Alteration of deposit Alteration consists of sericitized schist in both the hanging and footwall of the deposit.

Production and reserves

Workings or exploration At least three drill holes to a maximum depth of 470 feet were completed in the 1970s (O'Connor and others, 1989). Channel sampling and grab samples contain up to 11% combined lead and zinc, and 10 grams of silver per ton. Zones up to 1 meter wide contain 1% tin (Nokleberg and others, 1994).
Indication of production None
Reserve estimates Based on limited data a tentative resource of 5.5 million pounds of tin has been identified (O'Connor and others, 1989). There are no estimates of base metal reserves.

References

MRDS Number 10307531

References

Nokleberg, W.J., and (seven) others, 1994, Metallogeny and major mineral deposits of Alaska and Metallogenic map of significant metalliferous lode deposits and placer districts of Alaska, in Plafker, G. and Berg, H.C., eds., The Geology of Alaska: Geological Society of America, DNAG, The Geology of North America, Vol.. G1, p. 855-904, Plate 11, scale 1:2,500,000.
Reporters N. Van Wyck (Stevens Exploration Management Corporation)
Last report date 4/7/2000